Lamp fixture having dichoric filter arrangement for selectively directing heat and light

ABSTRACT

A fixture for a lamp which emits both light and heat. A first dichroic filter which reflects light and transmits heat, and a second dichroic filter which reflects heat and transmits light, are movably positioned relative to each other near the lamp, so as to be capable of selectively directing both heat and light from the lamp in a given direction, or directing light only from the lamp in a given direction.

i United States Patent [1 Kim [ Oct. 30, 1973 [75] Inventor:

[ LAMP FIXTURE HAVING DICHORIC FILTER ARRANGEMENT FOR SELECTIVELYDIRECTING HEAT AND LIGHT Sang-Chul Kim, Cleveland Heights, Ohio [73]Assignee: General Electric Company,

Schenectady, N.Y.

[22 Filed: June 23, 1972 [21] Appl. No.: 265,444

Related US. Application Data [63] Continuation of Ser. No. 117,484, Feb.22, 1971,

abandoned.

[52] US. Cl 240/4l.34 R, 240/47, 240/103 A [51'] Int. Cl. F211 15/02[58] Field of Search 240/47, 103 A, 41.35

[56] References Cited UNITED STATES PATENTS 7/1963 Strawick 240/471,209,235 12/1916 vass ..240/103A FOREIGN PATENTS 0R APPLICATIONS391,206 2 1924 Germany 24'0 103 A Primary ExaminerSamuel S. MatthewsAssistant Exam'inerMonroe H. Hayes Attorney-Norman C. Fulmer et al.

57 5 'ABSTRACT A fixture for a lamp which emits both light and heat. I

A firstdichroic filter which reflects light and transmits heat, and asecond dichroic filter which reflects heat and transmits light, aremovably positioned relative to each other near the lamp, so as to becapable of selectively directing both heat and light from the lamp in agiven direction, or directing light only from the lamp in a givendirection.

5 Claims, 5 Drawing Figures MENU-11061301913 3,769,503

Invervtor: Sang ChuL Kim His AttOT'TWH LAMP FIXTURE HAVING DICI-IORICFILTER ARRANGEMENT FOR SELECTIVELY DIRECTING HEAT AND LIGHTCROSS-REFERENCES TO RELATED APPLICATIONS This is a continuation ofapplication Ser. No. 177,484, filed Feb. 22, 1971, now abandoned.

BACKGROUND OF THE INVENTION The invention is in the field of lightingfixtures, and is particularly directed to the use of dichroic filtersfor controlling the heat emitted by light sources.

Most of the commonly used light sources emit heat, in addition to light.Incandescent lamps and are lamps generally emit relatively greateramounts of heat, and fluorescent lamps emit relatively less heat, incomparison to the amount of light emitted. In certain lightingapplications, such as general room illumination in cold weather orillumination of tropical fish in a merchandise display, it is desiredthat the heat of the lamp accompany the illumination. In certain otherlighting applications, such as general room illumination in hot weatheror illumination of flowers in a merchandise display, the heat producedby the light source is undesirable, and for such purposes dichroicfilter lamps have been developed which emit light in one direction andemit the heat in the reverse direction. Dichroic filters can be madewhich will reflect or transmit various wavelengths of radiation. Forexample, one type of dichroic filter reflects visible light rays andtransmits infrared (heat) rays, and another type functions in reverse soas to transmit light rays and reflect heat rays, Such filters usuallyare made by coating a plurality of layers of certain materials onto atransparent support member such in glass. In many lighting applications,it is awkward or unfeasible to change the type of lamp, from warm" typeto cool type, or vice versa, as the need or desire changes for havingheat from the lamp accompany, or not accompany, the light therefrom.

SUMMARY OF THE INVENTION Objects of the invention are to provide animproved lamp fixture, and to provide a dichroic filter arrangementwhich is quickly and readily adjustable for selectively causing heatfrom a light source to accompany, or not accompany, the light therefrom.

The invention comprises, briefly and in a preferred embodiment, a firstdichroic filter member positioned with respect to a light source andadapted to reflect light from said light source in a given direction,said first dichroic filter member being further adapted to transmittherethrough heat from said light source, and a second dichroic filtermember movably mounted so as to be alternatively positionable betweensaid light source and said first dichroic filter member or on theopposite side of said light source away from said first dichroic filtermember, said second dichroic filter member being adapted to reflect heatand transmit light from said light source. Preferably, said first andsecond dichroic filter members are in the general shape FIG. 1 is across-sectional view of a preferred embodiment of the invention, showingtwo dichroic filter members arranged to reflect light in one directionand heat in the opposite direction;

FIG. 2 is a cross-sectional view of the same apparatus as FIG. 1, withthe dichroic filters positioned so as to reflect both heat and lightfrom the lamp in the same direction;

FIG. 3 is a perspective view, toward the bottom thereof, of anarrangement of dichroic filters in the shape of hollow hemispheres;

FIG. 4 is a perspective view of an arrangement in which the dichroicfilters are in the shape of hollow semi-cylinders; and

FIG. 5 is a side view of the embodiment of FIG. 4.

A DESCRIPTION OF THE FREE ERRED EMBODIMENTS In FIG. I, a ligh-emittingsource 11 (which also emits heat) is held in position by means of asocket or other suitable arrangement, and may be a conventionalhousehold light bulb, or other type of lamp such as a fluorescent lamp,arc lamp, or metallic-vapor lamp. A first dichroic filter member 12, ofthe type which reflects visible light and transmits heat, is positionednear the light source 11 and is contoured to direct the light in a givendirection, such as toward a person 14, as indicated by the light raysdesignated L." A second dichroic filter member 16, of the type whichreflects heat and transmits light, is movably positioned with respect tothe light source l1 and first filter 12, and is contoured in a curvedshape as shown, so as to be rotatable generally about the light source11. When the second filter member 16 is in the position shown in FIG. 1,i.e., on the other side of the light source 11 from the first filtermember 12, it reflects heat from the light source 11 rearwardly, awayfrom the direction of the reflected light rays L, and through the firstdichroic filter member 12, as indicated by the heat rays H. Light fromthe source 11 and from the reflector 12 is readily transmitted throughthe second dichroic filter member 16, so that in the arrangement of FIG.1 light is effectively and efficiently directed in a desired direction,unaccompanied by heat from the light source ll.

When the second dichroic filter member 16 is swung into the positionshown in FIG. 2, i.e., to a position between the light source 11 and thefirst dichroic filter member 12, it reflects the heat rays H in the samegiven direction as the light rays L, as indicated in FIG. 2. The lightrays reflected from the first filter member 12, pass efficiently andunobstructed in both directions through the second filter member 16,whereby the overall effectiveness and efficiency of light directed inthe desired direction, both as reflected from the member 12, and asemitted directly from the light source 11, is the same in thearrangements of each of FIGS. 1 and 2. The filter member 16 may bepivoted as will be described in connection with FIGS. 3 and 4, so as -tobe manually adjustable to the desired position. If desired, mechanicalmeans such as chain, handle, or lever means, may be provided to assistin readily making the adjustment. In the position shown in FIG. l, inwhich the light fixture of the invention emits light only, without heat,in a desired direction, the fixture is particularly suitable for use asa reading lamp in a warm room, or as a lighting fixture in a store,where it is desired to illuminate merchandise without adding heat to thevicinity. In the position shown in FIG. 2, the light fixture isparticularly suited for use as a reading lamp in a'cold room where heatfrom the light source 1 1 adds desired warmth, and also is suitable as adisplay lighting fixture where it is desired to add heat to the vicinityof the displayed merchandise.

Each of the dichroic filter members 12 and 16 may be made in well-knownmanner, such as by depositing ter members 12 and 16 are generally in theshape of hollow hemispheres, the filter member 16 being sup ported bypivotal mounting. means 17 so that the filter member 16 is rotatableabout an axis extending approximately along a diameter thereof andthrough the light source 11, so that it can be positioned as shown inFIG. 3, which corresponds to the arrangement of FIG. 1, or alternativelymaybe rotated to correspond to the arrangement shown in FIG. 2, so as tocause heat from the light source to accompany the light.

In the embodiment shown in FIGS. 4 and 5, the light source 11 is ofelongated shape, such as a cylindrical incandescent lamp or dischargelamp, and the dichroic filtermembers l2 and 16 are in the shape ofhollow semicylinders, the filter member 16 being supported by pivotalmeans 18 so as to be rotatable about an axis extending generallycoextensive with the axis of the filter member 16 and with the axis ofthe light source 11. In the position shown in FIG. 4, the second filter16 causes heat to be directed so as to accompany the light, whereas inFIG. 5 the second filter member 16 is shown in a position correspondingto the position shown in FIG. 1, so that heat from the light source 11does not accompany the light therefrom.

While the second reflector member 16 is shown as being generally smallerthan that of the first filter member 12, and arranged to be positionablebetween the light source 11 and first filter member 12, it could, ifdesired, be made larger than the first filter member 12, so as to beswingable behind the first filter member 12 come apparent to personsskilled in the art, and will fall Within the scope of invention asdefined in the following claims.

vWhat I claim as new and desire to secure by Letters Patent of theUnited States is:

l. A lamp fixture for use with a light source which emits heat inaddition to light, wherein the improvement comprises a first dichroicfilter member adapted to reflect light and transmit heat from said lightsource and fixedly positioned with respect to said source a givendistance therefrom to reflect light from said source in a givendirection, and a second dichroic filter member adapted to reflect heatand transmit light from said light source, and mounting means movablypositioning said second filter with respect to the position of saidlight source whereby said second filter can be selectively rotated aboutsaid position of the light source to positions on opposite sides thereofin alignment with said given direction of light so as to reflect heatfrom said light source in said given direction or away from said givendirection.

' 2. A lamp fixture as claimed in claim 1, in which said first andsecond filter members are in the shape of hollow hemispheres with theconcave surfaces thereof facing toward said position of the light sourceand contoured to respectively reflect said light'and heat inpredetermined patterns, and in which said mounting means comprisespivotal means permitting said second filter member to be swung about anaxis extending substantially along a diameter thereof and through ornear said position of the light source.

3. A lamp fixture as claimed in claim 2, in which said second filtermember is positioned relatively closer to said position of the lightsource than is said first filter member, whereby said secondfiltermember can be rotated to a position between said first filter member andsaid position of the light source.

4. A lamp fixture as claimed in claim I, in which said first and secondfilter members are in the shape of hollow semicylinders with the concavesurfaces thereof facing toward said position of the light source andcontoured to respectively reflect said light and heat in predetermined.patterns, and in which said mounting stantially along the axis of saidsecond semicylinder and with respect to the light source 11. A socketfor the 4 through or near said position of the light source.

5. A lamp fixture as claimed in claim 4, in which said second filtermember is positioned relatively closer to said position of the lightsource than is said first filter member, whereby said second filtermember can be rotated to a position between said first filter member andsaid position of the'light source.

mg UNITED STATES PATENT OFFICE 5 CERTIFICATE OF CORRECTION Pat nt N3,769,503 Dated October so, 1973 Inventor(s) Sang-Chul Kim In the Title,change "DICHORIC" to --nIcH1ioIc-'- Signed and sealed this 5th day ofMar ch 197 1..

(SEAL) Attest: I

EDWARD M.FLETCHER, JR. 7 c. MARSHALL DA'NN Attesting OffiCer-Commissioner pf .P ate nt's

1. A lamp fixture for use with a light source which emits heat inaddition to light, wherein the improvement comprises a first dichroicfilter member adapted to reflect light and transmit heat from said lightsource and fixedly positioned with respect to said source a givendistance therefrom to reflect light from said source in a givendirection, and a second dichroic filter member adapted to reflect heatand transmit light from said light source, and mounting means movablypositioning said second filter with respect to the position of saidlight source whereby said second filter can be selectively rotated aboutsaid position of the light source to positions on opposite sides thereofin alignment with said given direction of light so as to reflect heatfrom said light source in said given direction or away from said givendirection.
 2. A lamp fixture as claimed in claim 1, in which said firstand second filter members are in the shape of hollow hemispheres withthe concave surfaces thereof facing toward said position of the lightsource and contoured to respectively reflect said light and heat inpredetermined patterns, and in which said mounting means comprisespivotal means permitting said second filter member to be swung about anaxis extending substantially along a diameter thereof and through ornear said position of the Light source.
 3. A lamp fixture as claimed inclaim 2, in which said second filter member is positioned relativelycloser to said position of the light source than is said first filtermember, whereby said second filter member can be rotated to a positionbetween said first filter member and said position of the light source.4. A lamp fixture as claimed in claim 1, in which said first and secondfilter members are in the shape of hollow semicylinders with the concavesurfaces thereof facing toward said position of the light source andcontoured to respectively reflect said light and heat in predeterminedpatterns, and in which said mounting means comprises pivotal meanspermitting said second filter member to be swung about an axis extendingsubstantially along the axis of said second semicylinder and through ornear said position of the light source.
 5. A lamp fixture as claimed inclaim 4, in which said second filter member is positioned relativelycloser to said position of the light source than is said first filtermember, whereby said second filter member can be rotated to a positionbetween said first filter member and said position of the light source.